Controlling apparatus



March 7, 1950 BLOMBERG 2,499,451

CONTROLLING APPARATUS Original Filed Oct. 21, 1942 2 Sheets-Sheet lINVENTOR: 4 K, H. Blomherg 6 flf'forweyd.

March 7, 1950 K. H. BLOMBERG 2,499,451

CONTROLLING APPARATUS Original Filed Oct. 21, 1942 2 Sheets-Sheet 2 IINVENTOR K. H Biomery BY M DWM igforwey Patented Mar. 7, 1950 2,499,451CONTROLLING APPARATUS Knut Hugo Blomberg, New York, N. Y., assignor toTelefonaktiebolaget holm, Sweden L. M. Ericsson, Stock- Originalapplication October 21, 1942, Serial No.

Divided and this application April 16,

1946, Serial No. 662,439. In Sweden October 6 Claims.

is not exposed to mechanical stresses.

This application is a division of my earlier application filed October21, 1942, Serial Number 462,868, now U. S. Patent 2,435,027, issuedJanuary 27, 1948.

The invention will be more closely described with reference to theaccompanying drawings in which Fig. 1 is a perspective view of a deviceaccording to the invention, Fig. 2 is a circuit diagram, Figs. 3 and 4show the contact spring assembly with the springs in differentpositions. 0

On a pivot l is placed a U-shaped arm 2 which at the one end supports arelay 3 and at the other is formed as a pointer 4 that is movable over ascale 5. The arm 2 is adjustable in different positions by turning roundthe pivot l which turning is produced by the wheel I actuating a toothedgear segment 6. The measuring instrument 8 is arranged in such a waythat the axis of the driving axle 8 of the pointer l0 coincides with theaxis of the pivot I. The pointer axle supports the pointer In, theprolongation l I of which cooperates with one l5 of the two springassemblies l4 and [5 of the relay 3. The contacts 14a and Nb of thespring assembly [4 are closed when the relay is in its rest position butare opened when the armature l6 of the relay is attracted by a stud onthe armature lifting spring Mb. The spring assembly 15, the constructionof which appears from the Figs. 1, 3 and 4, comprises two contactsprings 19 and 20. The latter is furnished with a reinforcement 2| andstuds l8 and 22. The spring 19 is provided with a stud 28. Above thecontact is arranged a stationary bridge 21 provided with a track 32adapted, at times, to receive the stud 28. When the armature I6 isattracted and presses the stud It, the springs 20 and is are lifted, thelatter by means of the stud 22. A closing of the contact between thesesprings can not occur if the movement upwards of the spring I9 is notlimited. This closing is however affected in the position shown in Figs.3 and 4 when the pointer prolongation ll takes such a position that itlies across and obstructs the track 32. When the two springs l9 and 20are then lifted, the stud 28 of the spring is cannot 55 temperature in afurnace.

2 penetrate into the track 32. The movement upwards of the spring 19will therefore be stopped as soon as the stud 28 engages theprolongation H. During th continued movement of the armature only thespring 23 will be lifted upwards and in so doing it makes contact withthe spring l9, as shown in Fig. 4. If the prolongation H assumes aposition laterally of the spring assembly as shown in Fig. 1 with dottedlines the track 32 will be open and the stud 28 will push into the trackwhen the springs are being lifted. The two springs will then be liftedparallel to each other during the whole movement of the armature andthere will be no contact between them. In order to prevent the stud 28from striking and pressing hard against the pointer if the pointerprolongation H is just in front of the track 32 there is a spring 25,Fig. 3, which is furnished with a stud 24. The spring is bent at itsfree end in such a way that a surface 29 facing the pointer prolongationis obtained. The spring is also furnished with a flap 26 for limitingthe movements of the pointer in one direction, Fig. 1. An opening 3|,Fig. 1, is arranged in the same spring 25 in such a way that the stud 28is able to move freely therein. When the contact springs 19,- 20, arebeing lifted at themovements of the armature the spring 25 will also belifted upwards by the stud 22 and stud 24. The surface 29 then will makecontact with the pointer prolongation H. During the continued movementupwards of the armature the free end of the spring 25 will be bentadjacent the stud 24 in such a way that it bears yieldably against theprolongation I l, as is shown in Fig. 4 and presses the prolongation llelastically against the bridge 21 before the stud 28 strikes against thesame.

Fig. 2 is a circuit diagram showing the invention applied to anarrangement controlling the M is a measuring instrument. Both itsterminals Tl are connected to a thermo couple in the furnace over theresistance R5. The mercury circuit breaker H is connected to a controlcircuit over the line T2,

which circuit supervises the connection and disconnection of a heater inthe furnace. This heater will be connected when the circuit breaker Htakes the position shown in Fig. 2. The relay 3 is connected to thewires a, b, over the glow lamp G, the resistance R4 and the rectifierLa. The

wires a, b are connected with an alternating current source. KI and K2are condensers. The relay 3 is energized periodically in known manner bymeans of the glow lamp G and the condenser Kl, the intervals between twoenergize.-

tions being controlled through the resistance R4. A rectifier bridge Llis connected to the wires a, b over the resistance R3, said bridgefeeding a circuit of the slow release relay R. Every time the relay 3 isenergized the contact between the springs Ma and Nb in the springassembly M of the relay will be broken and the two springs l9 and 20will be lifted. In dependence upon the position of the pointerprolongation II, the contact between I 9 and 2B then will either remainopen or be closed. If the pointer II is just in front of I9 and 20, thisimplies that the right temperature in the furnace is obtained. At thistemperature, which must not be exceeded, the contact [9, 20 will beclosed at the next momentary attraction of the relay, whereby the slowrelease relay R is energized and closes a holding circuit, for itselfover contacts rl, r2. After deenergization of the relay, said holdingcircuit is closed over the contact Ma, M2). on attraction of the relay Rthe circuit breaker H will be operated whereby the above describedheater in the furnace will be disconnected. The heater will continue tobe disconnected for as long a time as the temperature is at the value,which corresponds to the position of the pointer ll right in front ofthe springs I9, 20. In this position of the pointer the relay R isenergized. The relay R will be energized also during the periodicalenergizations of the relay every energization of the relay 3 will beclosed at the same time as the contact Ma, 14bwill be broken. If thetemperature falls and the pointer thus will take such a position that itcannot cooperate With the springs I9, 20, the contact I9, 20 Will not beclosed at the next energization of the relay 3. Said contact remainsbroken and at the same time also the contact Ma, Mb is being broken. Thecircuit of the relay R will, therefore, be broken and relay Rde-energized whereby the contact TI, 12 will be broken and the circuitbreaker H restored to its rest position in which the heater is againconnected. The temperature increases thereby again to a valuecorresponding to the pointer ll coming right in front of the springs l9, 29 whereby the heater will then be disconnected as above described.It is evident that the heater will be alternately connected and dis- 3as the contact I 9, 20 at connected, the temperature through thisarrangement being thus maintained at a constant value.

What I claim is:

1. An automatic electric control apparatus comprising a movable pointer,a contact spring assembly, settable means for supporting said assemblyin adjusted positions along the path of movement of said pointer, saidspring assembly including contact springs movable into two differentrelative positions to make and break contact with each other, a studcarried by one of the contact springs, an abutment member having arecess for accommodating said stud, said pointer being adapted in apredetermined position thereof, to obstruct said recess and prevententry of the stud therein, and operating means effective to move thesprings from one to the other of said two positions when said recess isobstructed by said pointer and the movement of the first mentionedcontact spring is limited thereby, said operating means beingineffective to move the springs from said first to said second positionwhen the recess is unobstructed by said pointer and the stud is free toenter said recess.

2. An automatic electric control apparatus as claimed in claim 1 whereinan additional spring is provided and actuated by one of said contactsprings to yieldably bear on said pointer when the latter is in itsobstructing position.

3. An apparatus as claimed in claim 1 wherein a stud is provided tonormally retain the contact springs in spaced relation.

4. An apparatus as claimed in claim 1 wherein a stud is provided tonormally retain the contact springs in spaced relation and areinforcement carried by one of said contact springs.

5. An arrangement as claimed in claim 1 wherein said contact springs andoperating means are constituted by an electro-magnetic relay supportedupon said settable means.

6. An arrangement as claimed in claim 1, characterized by the provisionof a further pointer carried by said settable means and movable alongthe path of movement of said first mentioned pointer.

KNUT HUGO BLOMBERG.

N 0 references cited.

